SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d94525d69b007375d1a5c4e40c1e0ae2a0ba6115ed638048f4398fadeefccf' 
  AND token = 'ZeslC0fH4Uy/GFmmiz4zmr0vYI37TmUcWu0ZTRLgatc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}